The present invention relates to weaving looms of the type wherein a pulse or current of a fluid such as air is employed to carry weft across a shed and relates, more particularly, to a new and improved weft guidance tube for directing the pulse or current of fluid and the weft conveyed thereby across such shed, and to a novel segment for use in constructing such weft guidance tubes.
Guidance tubes for conducting weft through the shed of a loom are well known in the art as exemplified by the following U.S. Pat. Nos. 3,139,118 to Svaty, et als; 3,065,770 to Svaty, et als; 3,203,452 to Svaty, et als; 3,557,645 to Svaty, et als; 3,796,236 to Kamp; and 3,847,187 to Buran et al. Such guidance tubes rather typically include a row of segments cemented into a common mounting member, with each segment having an aperture therethrough into which a fluid such as air and weft entrained in the air are directed. Each segment has an outlet through which the weft can exit as the tube is withdrawn from the shed prior to beat up of the weft into the fabric being woven on the loom. In operation with such tubes it is essential that the segments when assembled in their common mounting member be arranged in virtually perfect alignment with respect to each other. That is to say, the apertures of all of the plurality of segments must be essentially perfectly aligned, the exit slots of the segments must similarly be in perfect alignment, and the segments must be uniformly and properly spaced from each other, all to the end that the weft and the air moving through the tube will not experience turbulence, interruption, or under escape from the tube, that the air will not undergo undue leakage out of the tube, and that the weft can readily exit from the tube at the proper instant without being trapped in any of the segments at the moment of beat up. In the absence of the characteristics just stated, the weft may not be properly propelled across the shed, and the weft may not fully exit from the tube at the proper instant. Either condition results in a weaving malfunction.
It has been found in practice with prior art weft guidance tubes that they are difficult to assemble, that such assembly represents a tedious and time-consuming task, and the requisite degree of alignment and spacing of the parts is extremely difficult to achieve. These difficulties obtain from a variety of independent shims or spacers located between individual segments to establish the gap therebetween. Further, in the prior art a mandrel or other means is employed in an effort to achieve the desired alignment of the apertures and exit slots of the plurality of segments. Further an epoxy or cement is used to fasten the segments in their mounting member. Keeping in mind that weft guidance tubes frequently include up to six or more segments per inch and that currently available weft guidance tubes commonly range up to 48 inches or more in length, it is readily apparent that proper assembly of such tubes is an extremely difficult and time-consuming task.
The present invention is particularly directed to a new and improved weft guidance tube which incorporates efficiencies not hereinbefore known in the art.